final newline

This function adds a final newline to the file, depending on your buffer EOL mode, if one is not present. It's suitable for connecting to the before-save event.

function final_newline()
    local len = buffer.length
    local last = string.char(buffer.char_at[len])
    if buffer.eol_mode == buffer.EOL_LF and last ~= '\n' then
        buffer:insert_text(len, '\n')
    elseif buffer.eol_mode == buffer.EOL_CR and last ~= '\r' then
        buffer:insert_text(len, '\r')
    elseif buffer.eol_mode == buffer.EOL_CRLF and last ~= '\n' then
        local last1 = string.char(buffer.char_at[len-2])
        if last1 ~= '\r' then
            buffer:insert_text(len, '\r\n')
        end
    end
end

events.connect(events.FILE_BEFORE_SAVE, final_newline)